Glycobiology Research and Training Center and Departments of Cellular, University of California, San Diego, La Jolla, California 92093-0687, USA.
J Biol Chem. 2012 Nov 2;287(45):38073-9. doi: 10.1074/jbc.M112.380584. Epub 2012 Sep 18.
Sialic acids (Sias) mediate many biological functions, including molecular recognition during development, immune response, and fertilization. A Sia-rich glycocalyx coats the surface of sperm, allowing them to survive as allogeneic cells in the female reproductive tract despite female immunity. During capacitation, sperm lose a fraction of their Sias. We quantified shed Sia monosaccharides released from capacitated sperm and measured sperm sialidase activity. We report the presence of two sialidases (neuraminidases Neu1 and Neu3) on mammalian sperm. These are themselves shed from sperm during capacitation. Inhibiting sialidase activity interferes with sperm binding to the zona pellucida of the ovum. A survey of human sperm samples for the presence of sialidases NEU1 and NEU3 identified a lack of one or both sialidases in sperm of some male idiopathic infertility cases. The results contribute new insights into the dynamic remodeling of the sperm glycocalyx prior to fertilization.
唾液酸（Sias）介导许多生物学功能，包括发育过程中的分子识别、免疫反应和受精。富含唾液酸的糖萼覆盖在精子表面，使它们能够在女性生殖道中作为同种异体细胞存活，尽管女性具有免疫力。在获能过程中，精子会失去一部分唾液酸。我们定量分析了从获能精子释放的脱落唾液酸单糖，并测量了精子唾液酸酶活性。我们报告了两种唾液酸酶（神经氨酸酶 Neu1 和 Neu3）存在于哺乳动物精子上。在获能过程中，这些酶本身也从精子上脱落。抑制唾液酸酶活性会干扰精子与卵子透明带的结合。对人类精子样本中唾液酸酶 NEU1 和 NEU3 的存在情况进行调查，发现一些男性特发性不育病例的精子中缺乏一种或两种唾液酸酶。研究结果为受精前精子糖萼的动态重塑提供了新的见解。
